Additive manufacturing for medical devices

ABSTRACT

An additive manufacturing system may include a heating cartridge defining an interior volume and at least one filament port. The system may include a heating element thermally coupled to the heating cartridge to heat the interior volume. The system may also include a filament handling system to feed at least one filament through the at least one filament port. The system may include a substrate handling system having at least a head stock. The system may include a controller configured to initiate or control movement of a substrate relative to the heating cartridge to apply a jacket to the substrate.

The present application claims the benefit of U.S. ProvisionalApplication No. 62/927,092, filed Oct. 28, 2019, which is incorporatedherein by reference in its entirety.

The disclosure generally relates to medical devices and, in particular,additive manufacturing of medical devices, such as catheters andimplantable stimulation leads.

A number of medical devices, such as medical catheters, are designed tobe navigated through tortuous paths in a human body, such as through apatient's vasculature. Medical catheters and leads are commonly used toaccess vascular and other locations within a body and to perform variousfunctions at those locations, for example, delivery catheters may beused to deliver medical devices, such as implantable medical leads.Medical catheters and leads may be designed to be sufficiently flexibleto move through turns, or curves, in the vasculature yet sufficientlystiff, or resilient, to be pushed through the vasculature. In manycases, such as those involving cardiovascular vessels, the route to thetreatment or deployment site may be tortuous and may present conflictingdesign considerations that may require compromises between dimensions,flexibilities, material selection, operational controls and the like.These contrasting properties can present challenges in designing andmanufacturing catheters. Existing manufacturing processes, such asconventional extrusion, may also limit options in designing andmanufacturing catheters.

SUMMARY

The techniques of the present disclosure generally relate to additivemanufacturing of medical devices, such as catheters and leads, thatallows for the use of a wider range of filament or pellet materials tocreate a wide range of resulting catheter or lead characteristics. Forexample, a wider variety of hardness levels can be achieved compared toexisting techniques to produce catheters, catheter components, orimplantable devices. In particular, the present techniques allow forfeeding soft filaments at high feed forces during additivemanufacturing, or three-dimensional (3D) printing. Additionally, thepresent techniques may facilitate new catheters and implantable devices.

The details of one or more aspects of the disclosure are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the techniques described in this disclosurewill be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram that illustrates one example of anadditive manufacturing system according to the present disclosure.

FIG. 2 is a conceptual diagram that illustrates one example of anadditive manufacturing apparatus for use with, for example, the additivemanufacturing system of FIG. 1.

FIG. 3 is an image of one example of a subassembly for use with, forexample, the additive manufacturing system of FIG. 1.

FIG. 4 is an image of one example of the additive manufacturingapparatus of FIG. 2.

FIG. 5 is an image of one example of a first handling subassembly with atop portion removed for use with, for example, the additivemanufacturing system of FIG. 1.

FIG. 6 is a conceptual diagram that illustrates one example of aconcentricity guide for use with, for example, the additivemanufacturing system of FIG. 1.

FIG. 7 is an image of one example of a concentricity guide and a heatingblock for use with, for example, the additive manufacturing system ofFIG. 1.

FIG. 8 is a conceptual diagram that illustrates one example of a heatingcartridge for use with, for example, the additive manufacturing systemof FIG.1.

FIG. 9 is a conceptual diagram that illustrates one example of theheating cartridge of FIG. 8 in a different view.

FIG. 10 is a conceptual diagram that illustrates one example of an inletdie for use with, for example, the heating cartridge in the additivemanufacturing system of FIG. 1.

FIG. 11 is a conceptual diagram that illustrates another example of aninlet die for use with, for example, the heating cartridge in theadditive manufacturing system of FIG. 1.

FIGS. 12A-B are images of proximal and distal sides of examples ofcomponents of a heating cartridge in an unassembled state for use with,for example, the heating cartridge in the additive manufacturing systemof FIG. 1.

FIG. 13 is a conceptual diagram of that illustrates one example of acatheter that may be manufactured, before the substrate is removed,using the additive manufacturing system of FIG. 1.

FIG. 14 is an image of one example of a catheter that may bemanufactured using the additive manufacturing system of FIG. 1.

FIG. 15 is a conceptual diagram that illustrates one example of an inletor outlet die that may be used, for example, in the heating cartridge inthe additive manufacturing system of FIG. 1.

FIG. 16 is an image of one example of the inlet or outlet die of FIG. 15in a different view.

FIG. 17 is a conceptual diagram that illustrates another example of aninlet or outlet die that may be used, for example, in the heatingcartridge in the additive manufacturing system of FIG. 1.

FIG. 18 is a conceptual diagram that illustrates an example of an outletdie that may be used, for example, in the heating cartridge in theadditive manufacturing system of FIG. 1.

FIG. 19 is a flow diagram that illustrates one example of a method foruse with, for example, the additive manufacturing system of FIG. 1.

DETAILED DESCRIPTION

The present disclosure generally provides additive manufacturing systemsand methods for medical devices, such as catheters and leads, thatallows for the use of a wider range of filament or pellet materials tocreate a wide range of resulting catheter or lead characteristics. Forexample, a wider variety of hardness levels can be achieved compared toexisting techniques to produce catheters, catheter components, orimplantable devices. Additive manufacturing may also be described asthree-dimensional (3D) printing. The additive manufacturing systems ofthe present disclosure allow feeding soft filaments at high feed forces,which may facilitate a wider range of operating conditions forprototyping or manufacturing. Further, new catheters and implantable devices may be facilitated by the wider range filament materials andoperating conditions.

The systems and methods described herein allow for 3D printing ofmedical devices, which may facilitate constructions with uniquecombinations of properties which may enable new treatments. Uniquecatheter handling properties may be achieved by combining materials inways not traditionally combined in catheter manufacturing and mayinclude materials that are new to catheter construction. In addition, 3Dprinting may allow for including other accessories, such as steeringcapability via pull wires, in a space efficient manner.

In some embodiments, the systems and methods described herein mayfacilitate concurrently depositing multiple standard geometry 3Dprinting filament or pellet resin on a surface in an up to 360 degreeradial plane via a variable shape die, to produce various surfaceprofiles, onto the surface of a part moving in multiple planes includingradially.

In some embodiments, the systems and methods described herein mayfacilitate concurrently depositing multiple standard geometry 3Dprinting filament resin at varying thickness over a surface via varyingfilament feed rate, die size, and substrate velocity.

In some embodiments, the systems and methods described herein mayfacilitate utilizing multiple in-line pinch rollers to increasepush-ability of flexible standard geometry 3D printing filament resin.

In some embodiments, the systems and methods described herein mayfacilitate concurrently depositing multiple and varying stiffnessstandard geometry 3D printing filament resin at varying blend ratio toproduce varying flex modulus and color of deposited material.

In some embodiments, the systems and methods described herein mayfacilitate utilizing a lumen, which may be sized for standard geometry3D printing filament, made particularly of polytetrafluoroethylene(PTFE) liner tube for lubricity and TORLON polyamide-imide for advancedthermal properties, and designed for a single PTFE tube to channelfilament from pinch rollers into a heater cartridge, with heat break andheat sink characteristics provided by the TORLON, resulting in anincrease in filament “push-ability.”

In some embodiments, the systems and methods described herein mayfacilitate utilizing an alignment guide to support and align a movingpart while depositing standard geometry 3D printing filament resin onthe part's surface.

In some embodiments, the systems and methods described herein mayfacilitate utilizing tooling to assemble input and output dies in aconcentric manner for the process of depositing multiple standardgeometry 3D printing filament resin.

In some embodiments, the systems and methods described herein mayfacilitate utilizing input and output die geometries to facilitatevarious resin deposition profiles and also concurrently added materials,such as wires, etc., embedded within the deposited resin, which may beused with standard geometry 3D printing filament resin.

In some embodiments, the systems and methods described herein mayfacilitate utilizing variably tuned pinch roller pressure, used onstandard geometry 3D printing filament, to optimize grip andpush-ability per a given filament durometer.

As used herein, the term “or” refers to an inclusive definition, forexample, to mean “and/or” unless its context of usage clearly dictatesotherwise. The term “and/or” refers to one or all of the listed elementsor a combination of at least two of the listed elements.

As used herein, the phrases “at least one of” and “one or more of”followed by a list of elements refers to one or more of any of theelements listed or any combination of one or more of the elementslisted.

As used herein, the terms “coupled” or “connected” refer to at least twoelements being attached to each other either directly or indirectly. Anindirect coupling may include one or more other elements between the atleast two elements being attached. Either term may be modified by“operatively” and “operably,” which may be used interchangeably, todescribe that the coupling or connection is configured to allow thecomponents to interact to carry out described or otherwise knownfunctionality. For example, a controller may be operably coupled to aresistive heating element to allow the controller to provide anelectrical current to the heating element.

As used herein, any term related to position or orientation, such as“proximal,” “distal,” “end,” “outer,” “inner,” and the like, refers to arelative position and does not limit the absolute orientation of anembodiment unless its context of usage clearly dictates otherwise.

All scientific and technical terms used herein have meanings commonlyused in the art unless otherwise specified. The definitions providedherein are to facilitate understanding of certain terms used frequentlyherein and are not meant to limit the scope of the present disclosure.

Reference will now be made to the drawings, which depict one or moreaspects described in this disclosure. However, it will be understoodthat other aspects not depicted in the drawings fall within the scope ofthis disclosure. Like numbers used in the figures refer to likecomponents, steps, and the like. However, it will be understood that theuse of a reference character to refer to an element in a given figure isnot intended to limit the element in another figure labeled with thesame reference character. In addition, the use of different referencecharacters to refer to elements in different figures is not intended toindicate that the differently referenced elements cannot be the same orsimilar.

FIG. 1 shows one example of an additive manufacturing system 100according to the present disclosure. The system 100 may be configuredand used to produce a catheter, catheter component, lead, orsubassembly. The system 100 may use or include consumable filamentmaterials or pellet form resins having a wide variety of hardnesslevels. The system 100 may be configured to operate a wide variety ofprocess conditions to produce catheters, catheter components, leads, orsubassemblies using filaments or pellet form resins of various hardnesslevels. In general, the system 100 defines a distal region 128, ordistal end, and a proximal region 130, or proximal end. The system 100may include a platform 124 including a rigid frame to support one ormore components of the system.

As shown in the illustrated embodiment, the system 100 may include oneor more components, such as a heating cartridge 102, a heating element104, a filament handling system 106, an optional wire handling system107, a substrate handling system 108, a controller 110, and a userinterface 112. The filament handling system 106 may be operably coupledto the heating cartridge 102. The filament handling system 106 mayprovide one or more filaments 114 to the heating cartridge 102. Theoptional wire handling system 107 may be used to provide one or morewires 115 to the heating cartridge 102. The heating element 104 may beoperably coupled, or thermally coupled, to the heating cartridge 102.The heating element 104 may provide heat to melt filament material inthe heating cartridge 102 from the one or more filaments 114 provided bythe filament handling system 106. The optional wires 115 may not bemelted by the heating cartridge 102. The substrate handling system 108may be operably coupled to the heating cartridge 102. The substratehandling system 108 may provide a substrate 116 that extends through theheating cartridge. Melted filament material located in the heatingcartridge 102 may be applied to the substrate 116. The substrate 116 orthe heating cartridge 102 may be translated or rotated relative to oneanother by the substrate handling system 108. The substrate handlingsystem 108 may be used to move the substrate 116 or the heatingcartridge 102 relative to one another to cover the substrate 116 withthe melted filament material to form a jacket 118. The optional wires115 may be incorporated into the jacket 118 (e.g., molded into, beddedwithin, etc.).

The substrate 116 may also be described as a mandrel or rod. The jacket118 may be formed or deposited around the substrate 116. In someembodiments, the jacket 118 may be formed concentrically around thesubstrate 116. In one example, the jacket 118 is formed concentricallyand centered around the substrate 116.

When the system 100 is used to make a catheter or catheter component,the jacket 118 may be described as a catheter jacket. Some or all of thesubstrate 116 may be removed or separated from the jacket 118 and theremaining structure coupled to the jacket may form the catheter orcatheter component, such as a sheath. One example of a catheter that maybe formed by the system 100 is shown in FIG. 13.

The substrate 116 may be formed of any suitable material capable ofallowing melted filament material to be formed thereon. In someembodiments, the substrate 116 is formed of a material that melts at ahigher temperature than any of the filaments 114. One example of amaterial that may be used to form the substrate 116 includes stainlesssteel.

The controller 110 may be operably coupled to one or more of the heatingelement 104, the filament handling system 106, the substrate handlingsystem 108, and the user interface 112. The controller 110 may activate,or initiate or otherwise “turn on,” the heating element 104 to provideheat to the heating cartridge 102 to melt the filament material locatedtherein. Further, the controller 110 may control or command one or moremotors or actuators of various portions of the system 100. Furthermore,the controller 110 may control one or more motors or actuators thefilament handling system 106 to provide one or more filaments 114.Further, the controller 110 may control one or more motors or actuatorsof the substrate handling system 108 to move one or both of the heatingcartridge 102 or the substrate 116 relative to one another. Furtherstill, the controller 110 may send or receive data to the user interface112, for example, to display information or to receive user commands.Control of the components operably coupled to the controller 110 may bedetermined based on user commands received by the user interface 112. Insome embodiments, the user commands may be provided in the form of amachine-readable code or coding language.

Any suitable implementation may be used to provide the substratehandling system 108. In some embodiments, the substrate handling system108 may include one or more of a head stock 120, an optional tail stock122, and one or more motors coupled to or included in the head stock ortail stock. One or both of the head stock 120 and the tail stock 122 maybe coupled to the platform 124. A stock may be defined as a structurethat holds or secures the substrate 116 during formation of the jacket118. The head stock 120 is defined as the stock closest to the end ofthe substrate 116 where formation of the jacket 118 begins in theformation process. In the illustrated embodiment, the jacket 118 isshown proximal to the head stock 120 and distal to the heating cartridge102.

When the substrate 116 is secured by one or both stocks 120, 122, thesubstrate is generally positioned to pass through a substrate channeldefined by the heating cartridge 102. One or both stocks 120, 122 mayinclude a clamp or other securing mechanism to selectively hold thesubstrate 116. Such a clamp may be operably coupled to a substratemotor. In some embodiments, the substrate motor may be used to controlopening and closing of the clamp. In some embodiments, the substratemotor may be used to rotate the substrate 116 in a clockwise orcounterclockwise direction about a longitudinal axis 126. A translationmotor may be operably coupled between a stock 120, 122 and the platform124. In some embodiments, the translation motor may be used to translatethe stock 120, 122 in a longitudinal direction along the longitudinalaxis 126. In some embodiments, the translation motor also may be used totranslate the stock 120, 122 in a lateral direction different than thelongitudinal axis 126. The lateral direction may be orientedsubstantially orthogonal, or perpendicular, to the longitudinal axis126.

In some embodiments, the substrate handling system 108 may be configuredto move the head stock 120 at least in a longitudinal direction (forexample, parallel to the longitudinal axis 126) relative to the platform124. The substrate 116 may be fed through the substrate channel of theheating cartridge 102 by movement of the head stock 120 relative to theplatform 124. A distal portion of the substrate 116 may be clamped intothe head stock 120. The head stock 120 may be positioned close to theheating cartridge 102 at the beginning of the jacket formation process.The head stock 120 may move distally away from the heating cartridge102, for example in a direction parallel to the longitudinal axis 126.In other words, the head stock 120 may move toward the distal region 128of the system 100 while pulling the secured substrate 116 through theheating cartridge 102. As the substrate 116 passes through the heatingcartridge 102, melted filament material from the filament 114 may beformed or deposited onto the substrate 116 to form the jacket 118. Theheating cartridge 102 may be stationary relative to the platform 124. Insome embodiments, the tail stock 122 may be omitted.

In some embodiments, the substrate handling system 108 may be configuredto move the heating cartridge 102 at least in a longitudinal direction(along the longitudinal axis 126) relative to the platform 124. Thesubstrate 116 may be fed through the substrate channel of the heatingcartridge 102. A distal portion of the substrate 116 may be clamped intothe head stock 120. A proximal portion of the substrate 116 may beclamped into the tail stock 122. In one example, the heating cartridge102 may be positioned relatively close to the head stock 120 at thebeginning of the jacket formation process. The heating cartridge 102 maymove proximally away from the head stock 120. The heating cartridge 102may move toward the proximal region 130 of the system 100. As theheating cartridge 102 passes over the substrate 116, melted filamentmaterial may be deposited onto the substrate 116 to form a jacket. Thehead stock 120 and the tail stock 122 may be stationary relative to theplatform 124. In another example, the heating cartridge 102 may startnear the tail stock 122 and move toward the distal region 128.

One or more motors of the substrate handling system 108 may be used torotate one or both of the substrate 116 and the heating cartridge 102relative to one another. In some embodiments, only the substrate 116 maybe rotated about the longitudinal axis 126. In some embodiments, onlythe heating cartridge 102 may be rotated about the longitudinal axis126. In some embodiments, both the substrate 116 and the heatingcartridge 102 may be rotated about the longitudinal axis 126.

The heating cartridge 102 may be part of a subassembly 132. Thesubassembly 132 may be coupled to the platform 124. In some embodiments,one or more motors of the substrate handling system 108 may be coupledbetween subassembly 132 and the platform 124 to translate or rotate thesubassembly 132, including the heating cartridge 102, relative to theplatform 124 or the substrate 116. In some embodiments, one or moremotors of the substrate handling system 108 may be coupled between aframe of the subassembly 132 and the heating cartridge 102 to translateor rotate the heating cartridge relative to the platform 124.

In some embodiments, the substrate 116 may be rotated about thelongitudinal axis 126 relative to the heating cartridge 102 tofacilitate forming certain structures of the jacket. In one example, thesubstrate 116 may be rotated by one or both of the head stock 120 andthe tail stock 122 of the substrate handling system 108. In anotherexample, the heating cartridge 102 or subassembly 132 may be rotated bythe substrate handling system 108.

The system 100 may include one or more concentricity guides 134. Theconcentricity guide 134 may facilitate adjustments to the concentricityof the jacket around the substrate 116 before or after the substratepasses through the heating cartridge 102. The concentricity guide 134may be longitudinally spaced from the heating cartridge 102. In someembodiments, the spacing may be greater than or equal to 1, 2, 3, 4, or5 cm. The spacing may be sufficient to allow the jacket 118 to cool downand no longer be deformable. In some embodiments, one or moreconcentricity guides 134 may be positioned distal to the heatingcartridge 102 and to engage the jacket 118. In some embodiments, one ormore concentricity guides 134 may be positioned proximal to the heatingcartridge 102 to engage the substrate 116. The concentricity guide 134may mitigate drooping of the substrate 116 and may mitigatesusceptibility to eccentricity in the alignment of the stock 120, 122and the heating cartridge 102.

Any suitable implementation may be used to provide the filament handlingsystem 106. One or more filaments 114 may be loaded into the filamenthandling system 106. For example, filaments 114 may be provided in theform of wound coils. Filaments 114 may be fed to the heating cartridge102 by the filament handling system 106. In some embodiments, thefilament handling system 106 may include one, two, or more pinch rollersto engage the one or more filaments 114. In some embodiments, thefilament handling system 106 may include one or more motors. The one ormore motors may be coupled to the one or more pinch rollers to controlrotation of the pinch rollers. The force exerted by the motors onto thepinch rollers and thus onto the one or more filaments 114 may becontrolled by the controller 110.

In some embodiments, the filament handling system 106 may be configuredto feed the filaments 114 including at least a first filament and asecond filament. The jacket 118 may be formed from the material of oneor both of the filaments 114. The filament handling system 106 may becapable of selectively feeding the first filament and the secondfilament. For example, one motor may feed the first filament and anothermotor may feed the second filament. Each of the motors may beindependently controlled by the controller 110. Selective, orindependent, control of the feeds may allow for the same or differentfeed forces to be applied to each of the filaments 114.

The filaments 114 may be made of any suitable material, such aspolyethylene, PEBAX elastomer (commercially available from Arkema S.A.of Colombes, France), nylon 12, polyurethane, polyester, liquid siliconerubber (LSR), or PTFE.

The filaments 114 may have any suitable Shore durometer. In someembodiments, the filaments 114 may have, or define, a Shore durometersuitable for use in a catheter. In some embodiments, the filaments 114have a Shore durometer of at least 25 A and up to 90 A. In someembodiments, the filaments 114 have a Shore durometer of at least 25 Dand up to 80 D.

In some embodiments, the filament handling system 106 may provide a softfilament as one of the filaments 114. In some embodiments, a softfilament may have a Shore durometer less than or equal to 90 A, 80 A, 70A, 80 D, 72 D, 70 D, 60 D, 50 D, 40 D, or 35 D.

In some embodiments, the filament handling system 106 may provide a hardfilament and a soft filament having a Shore durometer less than the softfilament. In some embodiments, the soft filament has a Shore durometerthat is 10 D, 20 D, 30 D, 35 D, or 40 D less than a Shore durometer ofthe hard filament.

The system 100 may be configured to provide a jacket 118 between theShore durometers of a hard filament and a soft filament. In someembodiments, the filament handling system 106 may provide a hardfilament having a Shore durometer equal to 72 D and a soft filamenthaving a Shore durometer equal to 35 D. The system 100 may be capable ofproviding a jacket 118 having a Shore durometer that is equal to orgreater than 35 D and less than or equal to 72 D.

The system 100 may be configured to provide a jacket 118 having, ordefining, segments with different Shore durometers. In some embodiments,the system 100 may be capable of providing a jacket 118 having one ormore of a 35 D segment, a 40 D segment, 55 D segment, and a 72 Dsegment.

The filaments 114 may have any suitable width or diameter. In someembodiments, the filaments 114 have a width or diameter of 1.75 mm. Insome embodiments, the filaments 114 have a width or diameter of lessthan or equal to 1.75, 1.5, 1.25, 1, 0.75, or 0.5 mm.

Segments may have uniform or non-uniform Shore durometers. The system100 may be configured to provide jacket 118 having one or more segmentswith non-uniform Shore durometers. In some embodiments, the jacket 118may include continuous transitions between at least two different Shoredurometers, for example, as shown in FIG. 13.

The controller 110 may be configured to change a feeding force appliedto one or more of the filaments 114 to change a ratio of material in thejacket over a longitudinal distance. By varying the feeding force, thesystem 100 may provide different Shore durometer segments in a jacket118, whether uniform or non-uniform. In one example, sharp transitionsbetween uniform segments may be provided by stopping or slowinglongitudinal movement while continuously, or discretely with a largestep, changing the feeding force of one filament relative to anotherfilament of the substrate 116 relative to the heating cartridge 102. Inanother example, gradual transitions between segments may be provided bycontinuously, or discretely with small steps, changing the feeding forceof one filament relative to another filament while longitudinally movingthe substrate 116 relative to the heating cartridge 102.

The system 100 may be configured to provide a jacket 118 having varyingthicknesses. In some embodiments, the controller 110 may be configuredto vary one or more parameters, for example, at least one of: alongitudinal speed of the substrate 116 relative to the heatingcartridge 102, a feeding force applied to one or more filaments 114, andan amount of heat provided by the heating element 104. Varying one ormore of these parameters during formation of the jacket 118 may be usedto change a thickness of the jacket over a longitudinal distance. Insome embodiments, the controller 110 may be configured to vary one ormore of these parameters in conjunction with using a particular heatingcartridge (see FIG. 18).

The one or more wires 115 provided by the wire handling system 107 maybe introduced in any suitable manner. In some embodiments, the wires 115may be attached to the substrate 116 and pulled by movement of thesubstrate. One example of a wire is a pull wire that may be used tosteer the catheter produced by the system 100. In some embodiments, aparticularly shaped heating cartridge may be used to accommodate one ormore wires 115 (see FIGS. 15-16).

Any suitable type of heating element 104 may be used. In someembodiments, the heating element 104 may be a resistive-type heatingelement, which may provide heat in response to an electrical current.Other types of heating elements that may be used for the heating element104 include a radio frequency (RF) or ultrasonic-type heating element.The heating element 104 may be capable of providing heat sufficient tomelt the filaments 114. In some embodiments, the heating element 104 mayheat the filaments 114 to greater than or equal to 235, 240, 250, or 260degrees Celsius. In general, the one or more heating elements 104 may beused to heat the filaments 114 to any suitable melting temperature knownto one of ordinary skill in the art having the benefit of thisdisclosure.

Any suitable user interface 112 may be used to communicate with thecontroller 110. Non-limiting examples of user interfaces 112 include oneor more of a stationary or portable computer, a monitor or otherdisplay, a touchscreen, a keyboard, a mouse, a tablet, a phone, a knob,a switch, a button, and the like. In some embodiments, the userinterface 112 may allow the user to input direct commands to or to entercode to program operations of the controller 110.

In one example, a program may include various command lines, such as:

M567 P0 E 0:1

G1 X100 E50 F200

M567 P0 E 0.25:0.75

G1 X100 E50 F100

M567 P0 E 0.5:0.5

G1 X100 E50 F60

M567 P0 E 0.75:.25

G1 X100 E50 F50

M567 P09 E 1:0

G1 X100 E50 F50

Such a program may “print” the following catheter jacket segments:

-   -   a) 100 mm segment with a flow rate 50 at speed 200. Mixture        ratio 0% material 1 and 100% material 2    -   b) 100 mm segment with flow rate 50 at speed 100. Mixture ratio        25% material 1 and 75% material 2.    -   c) 100 mm segment with flow rate 50 at speed 60. Mixture ratio        0% material 1 and 50% material 2.    -   d) 100 mm segment with flow rate 50 at speed 50. Mixture ratio        75% material 1 and 25% material 2.    -   e) 100 mm segment with flow rate 50 at speed 50. Mixture ratio        100% material 1 and 0% material 2.

As used herein, the term “flow rate” refers to a filament feed rateaccording to any suitable unit of measurement. In some embodiments,material 1 may be 35 D PEBAX and material 2 may be 72D PEBAX. Ingeneral, as the mixture ratio transitions to a softer durometermaterial, the overall feed rate (F###) may decrease. Decreasing the feedrate may reduce the tendency for the softer durometer material to jam.Certain techniques described herein may reduce the need to decrease theoverall feed rate. The flow rate command (E###) may directly affect thewall thickness of the printed catheter jacket.

FIG. 2 shows one example of an additive manufacturing apparatus 200 ofthe additive manufacturing system 100 in an end view along thelongitudinal axis 126, which is illustrated as a circle and cross. Moredetail of some components of the additive manufacturing system 100 areshown, such as the heating cartridge 102 and the filament handlingsystem 106.

The heating cartridge 102 may include a heating block 202 at leastpartially defining an interior volume 204. The interior volume 204 maybe heated by the heating element 104. The heating element 104 may bethermally coupled to the heating block 202 to melt filament material inthe interior volume 204. In general the system 100 may be configured tomelt any portion of the filaments 114 in the interior volume 204. Theheating element 104 may be disposed in an exposed or exterior volume 502(FIG. 12A) defined in the heating block 202. The heating element 104 maybe positioned proximate to or adjacent to the interior volume 204. Insome embodiments, one, two, three, or more heating elements 104 may bethermally coupled to the heating block 202.

The heating block 202 may allow the substrate 116, which may be anelongate substrate or member, to pass through the heating block. Thesubstrate 116 may be able to extend, or pass, through the interiorvolume 204. The substrate channel 206 defined by the heating cartridge102 may extend through the interior volume 204. The substrate channel206 may extend in a same or similar direction as the substrate 116. Thesubstrate channel 206 may extend along the longitudinal axis 126.

A width or diameter of the interior volume 204 is larger than a width ordiameter of the substrate 116. The width or diameter of the interiorvolume 204 or the substrate 116 is defined in a lateral direction, whichmay be orthogonal to the longitudinal axis 126. In one example, thelateral direction may be defined along a lateral axis 210. In someembodiments, the clearance between the substrate 116 and interior volume204 is relatively small to facilitate changes in composition of filamentmaterial used to form the jacket 118 (FIG. 1) around the substrate 116.

The portion of the interior volume 204 around the substrate 116 mayreceive a flow of melted filament material from the filaments 114. Whenmore than one filament material is provided to the interior volume 204,the filament materials may flow and blend, or mix, around the substrate116.

In the illustrated embodiment, the filaments 114 includes a firstfilament 212 and a second filament 214. The first filament 212 may beprovided into the interior volume 204 through a first filament port 216at least partially defined by the heating block 202. The second filament214 may be provided into the interior volume 204 through a secondfilament port 218 at least partially defined by the heating block 202.Each filament port 216, 218 may be at least partially defined by theheating block 202. Each filament port 216, 218 may be in fluidcommunication with the interior volume 204.

The filaments 114 may be delivered to the interior volume 204 in thesame or different manners. In the illustrated embodiment, the firstfilament 212 is delivered to the interior volume 204 in a differentmanner than the second filament 214.

The filament handling system 106 may include a first handlingsubassembly 220. The first handling subassembly 220 may deliver thefirst filament 212 to the interior volume 204. The first handlingsubassembly 220 may include one or more pinch rollers 222. Each of theone or more pinch rollers 222 may be operably coupled to a motor. Anysuitable number of pinch rollers 222 may be used. As illustrated, thefirst handling subassembly 220 may include two sets of pinch rollers222. Pinch rollers 222 may be used to apply a motive force to the firstfilament 212 to move the first filament, for example, toward theinterior volume 204.

The heating cartridge 102 may include a first guide sheath 224. Thefirst guide sheath 224 may extend between the filament handling system106 and the interior volume 204. The first guide sheath 224 may becoupled to the heating block 202. The first guide sheath 224 may extendinto the first filament port 216 from an exterior of the heating block202. The first guide sheath 224 may define a lumen in fluidcommunication with the interior volume 204. An inner width or diameterof the lumen may be defined to be greater than a width or diameter ofthe first filament 212. The first filament 212 may extend through thefirst guide sheath 224 from the pinch rollers 222 of the first handlingsubassembly 220 to the first filament port 216 and extend distally pastthe first guide sheath 224 into the interior volume 204.

As used herein with respect to the filaments 114, the term “distal”refers to a direction closer to the interior volume 204 and the term“proximal” refers to a direction closer to the filament handling system106.

In some embodiments, a proximal end of the first guide sheath 224 mayterminate proximate to one of the pinch rollers 222. A distal end of thefirst guide sheath 224 may terminate at a shoulder 226 defined by thefirst filament port 216. A distal portion or distal end of the firstguide sheath 224 may be positioned proximate to or adjacent to theinterior volume 204.

The inner width or diameter of the lumen of the first guide sheath 224may be defined to be substantially the same or equal to an inner widthor diameter of the first filament port 216, such as a smallest innerwidth or diameter of the first filament port. In other words, an innersurface of the first guide sheath 224 may be flush with an inner surfaceof the first filament port 216.

In some embodiments, the heating cartridge 102 may include a supportelement 228. The support element 228 may be coupled to the first guidesheath 224. The first guide sheath 224 may extend through a lumendefined by the support element 228. The support element 228 may beproximate to the heating block 202. In the illustrated embodiment, thesupport element 228 is coupled to the heating block 202. The supportelement 228 may include a coupling protrusion configured to bemechanically coupled to a coupling receptacle 230 defined by the firstfilament port 216. In some embodiments, the coupling receptacle 230 maydefine threads and the coupling protrusion of the support element 228may define complementary threads.

The coupling receptacle 230 may terminate at the shoulder 226 of thefirst filament port 216. The coupling protrusion of the support element228 may be designed to terminate at the shoulder 226. In someembodiments, a distal end of the support element 228 and the distal endof the first guide sheath 224 may engage the shoulder 226. In otherembodiments, the distal end of the support element 228 may engage theshoulder 226 and the distal end of the first guide sheath 224 may engagea second shoulder (not shown) defined by the first filament port 216distal to the shoulder 226.

When the first filament port 216 defines one shoulder, the firstfilament port 216 may define at least two different inner widths ordiameters. The larger inner width or diameter may be sized to thread thesupport element 228 and the smaller inner width or diameter may be sizedto match the inner width or diameter of the first guide sheath 224.

When the second filament port 218 defines two shoulders, the firstfilament port 216 may define at least three different inner widths ordiameters. The largest inner width or diameter may be sized to threadthe support element 228. The intermediate inner width or diameter may besized to receive a distal portion of the first guide sheath 224. Thesmallest inner width or diameter may be sized to match the inner widthor diameter of the first guide sheath 224.

The filament handling system 106 may include a second handlingsubassembly 232. The second handling subassembly 232 may deliver thesecond filament 214 to the interior volume 204. The second handlingsubassembly 232 may include one or more pinch rollers 222. Each of theone or more pinch rollers 222 may be operably coupled to a motor. Anysuitable number of pinch rollers 222 may be used. As illustrated, thesecond handling subassembly 232 may include one set of pinch rollers222. Pinch rollers 222 may be used to apply a motive force to the secondfilament 214.

The heating cartridge 102 may include one or more of a second guidesheath 234, a heat sink 236, and a heat break 238. The second guidesheath 234 may extend at least between the second handling subassembly232 and the heat sink 236. The second guide sheath 234 may be coupled tothe heat sink. The second guide sheath 234 may be coupled to the secondhandling subassembly 232. The heat sink 236 may be coupled to the heatbreak 238. The heat break 238 may be coupled to the heat block 202. Theheat break 238 may extend into the second filament port 218 from anexterior of the heating block 202.

The second guide sheath 234 may define a lumen in fluid communicationwith the interior volume 204. The second filament 214 may extend throughthe second guide sheath 234 from the second handling subassembly 232 tothe heat sink 236, through the heat sink 236, through the heat break,and through the second filament port 218. In some embodiments, thesecond guide sheath 234 may extend to the pinch rollers 22 in the secondhandling subassembly 232. In some embodiments, the second guide sheath234 may extend at least partially into the heat sink 236.

The heat break 238 may be proximate to the heating block 202. The heatbreak 238 may be positioned between the heat sink 236 and the heatingblock 202. The heat break 238 may include a coupling protrusionconfigured to mechanically couple to a coupling receptacle 240 definedby the second filament port 218. In some embodiments, the couplingreceptacle 240 may define threads and the coupling protrusion of theheat break 238 may define complementary threads. The second filamentport 218 may include one or more shoulders such as those described withrespect to the first filament port 216, except that the second filamentport 218 may not be configured to receive the second guide sheath 234.The inner width or diameter of the support element 228 may be largerthan the inner width or diameter of the heat break 238, for example, toaccommodate the outer width or diameter of the first guide sheath 224.In other embodiments, the second filament port 218 may be configured toreceive the second guide sheath 234 in a similar manner to the firstfilament port 216 receiving the first guide sheath 224.

Any suitable material may be used to make the guide sheaths 224, 234. Insome embodiments, one or both guide sheaths 224, 234 may include asynthetic fluoropolymer. One or both guide sheaths 224, 234 may includepolytetrafluoroethylene (PTFE). Another suitable material may include anultra-high molecular weight polyethylene (UHMWPE).

Any suitable material may be used to make the support element 228. Insome embodiments, the support element 228 may be a thermal insulator.The support element 228 may include a thermoplastic. The support element228 may be made of a polyamide-imide, such as a TORLON polyamide-imide(commercially available from McMaster-Carr Supply Co. of Elmhurst,Illinois). Other suitable materials may include liquid-crystal polymer,polyaryletherketone (PAEK), polyphenylene sulfide, and polysulfone.

The support element 228 may provide mechanical support to the firstguide sheath 224. The support element 228 may include a substantiallyrigid material. In some embodiments, the support element 228 include amaterial having a higher durometer than material used to make the firstguide sheath 224.

Any suitable material may be used to make the heat sink 236. The heatsink 236 may include a high thermal conductivity material. In someembodiments, the heat sink 236 includes aluminum.

Any suitable material may be used to make the heat break 238. The heatbreak 238 may include a low thermal conductivity material. In someembodiments, the heat break 238 includes titanium. The heat break 238may include a necked portion to reduce the amount of material between aproximal portion and a distal portion of the heat break. The neckedportion may facilitate a reduced thermal conductivity between theproximal portion and the distal portion of the heat break 238.

In general, use of the apparatus 200 may facilitate using softerfilaments at high feed forces and pressures, which tend to compress thesoft filament and may result in jamming. Using higher feed forces andpressures may allow for a greater range of process conditions and mayprovide a consistent jacket around the substrate. In particular, use ofthe first guide sheath 224 extending at least partially into the firstfilament port 216 may facilitate the use of softer filament and greater“push-ability.” Additionally, or alternatively, the use of the supportelement 228 may also facilitate the use of softer filament and greater“push-ability.”

FIG. 3 is an overhead perspective image showing one example of thesubassembly 132. As illustrated, the subassembly 132 includes theconcentricity guide 134 aligned with heating block 202 alonglongitudinal axis 126, two heating elements 104 coupled to the heatingblock, the support element 228 coupled to the heating block, the firstguide sheath 224 coupled to the support element 228, the first handlingsubassembly 220 including a motor 302 and coupled to the first guidesheath, the heat sink 236 coupled to the second guide sheath 234, andthe second handling subassembly 232 including another motor 302 coupledto the second guide sheath. In some embodiments, one, two, three, ormore heating elements 104 may be used.

FIG. 4 is an end perspective image showing one example of the additivemanufacturing apparatus 200. As illustrated, the apparatus 200 includesthe heating block 202 at least partially defining the substrate channel206, a first guide sheath 224 extending along the lateral axis 210coupled to the first handling subassembly 220, the support element 228coupled to the first guide sheath and to the heating block, the secondguide sheath 234 coupled to the second handling subassembly 232, theheat sink 236 coupled to the second guide sheath, and the heat break 238coupled to the heat sink and the heating block.

FIG. 5 is an overhead perspective image showing one example of the firsthandling subassembly 220 with a top portion removed. The first handlingsubassembly 220 includes two sets of pinch rollers 222 coupled to one ofthe motors 302. The first handling subassembly 220 forms a channel 304configured to receive the first filament 212 (FIG. 2). A proximal end ofthe first guide sheath 224 extends into the channel 304 of the firsthandling subassembly and terminates proximate to the distal pinch roller222. In particular, the first guide sheath 224 terminates just distal tothe most distal pinch roller 222.

FIG. 6 shows one example of the concentricity guide 134. In someembodiments, the concentricity guide 134 may facilitate supporting thesubstrate 116 or the jacket 118 around the substrate 116. In someembodiments, the concentricity guide 134 may facilitate centering thejacket 118 around the substrate 116. The concentricity guide 134 may actupon (e.g., be in contact with, support, etc.) the jacket 118 afterleaving the heating cartridge 102 (FIG. 2) and the jacket material iscooled down and no longer deformable.

The concentricity guide 134 may include a stationary member 312 thatdefines a channel 306. The channel 306 may be sized to receive thesubstrate 116 or the substrate 116 covered by the jacket 118. Theconcentricity guide 134 may include an adjustable member 308. Theadjustable member 308 may be configured to laterally position (e.g.,left or right within the channel 306 as shown) the substrate 116 or thejacket 118 covering the substrate 116 relative to the channel 306. Theadjustable member 308 may be adjustable coupled to the stationary member312. In some embodiments, the adjustable member 308 may be rotatablycoupled to the stationary member 312.

FIG. 7 is a side perspective image showing one example of theconcentricity guide 134 in use with the heating block 202. Asillustrated, the substrate 116 extends through the substrate channel 206of the heating block 202 and is coated with the jacket 118. Theconcentricity guide 134 (without the adjustable member) is shownsupporting the jacket 118 around the substrate 116.

FIG. 8 shows a partial cross-sectional side view of one example of theheating cartridge 102. The heating cartridge 102 or the heating block202 may extend from a proximal side 410 to a distal side 412. In someembodiments, the heating cartridge 102 may include one or more of theheating block 202, an inlet die 402 coupled to the proximal side 410 ofthe heating block, an outlet die 404 coupled to the distal side 412 ofthe heating block, a proximal retaining plate 406 to facilitateretaining the inlet die adjacent to the heating block, and a distalretaining plate 408 to facilitate retaining the outlet die adjacent tothe heating block.

The inlet die 402 and the outlet die 404 may be retained in any suitablemanner. In the illustrated embodiment, the outlet die 404 may beretained by a distal shoulder of the distal retaining plate 408. In someembodiments, the inlet die 402 may be retained by the proximal retainingplate 406 between a distal shoulder of the proximal retaining plate 406and a fastener 500 (see FIG. 12A), such as a nut with a lumen extendingthrough, which may be threaded to the retaining plate to engage aproximal surface of the inlet die. The retaining plates 406, 408 may befastened to the heating block 202 in any suitable manner.

The inlet die 402 may at least partially define a substrate inlet port414. The outlet die 404 may at least partially define a substrate outletport 416.

The inlet die 402 may at least partially define the interior volume 204.The outlet die 404 may at least partially define the interior volume204. In some embodiments, an exterior surface of the inlet die 402, aninterior surface of the outlet die 404, and an interior surface of theheating block 202 may cooperatively define the interior volume 204.

The substrate channel 206 may be described as extending from theproximal side 410 to the distal side 412 of the heating cartridge 102,or vice versa. The substrate channel 206 may extend through the interiorvolume 204. As shown, the substrate channel 206 may extend through oneor more of the proximal retaining plate 406, the inlet die 402, theheating block 202, the outlet die 404, and the distal retaining plate408.

FIG. 9 shows the heating block 202 used in the heating cartridge 102shown in FIG. 8. With the dies removed, an orifice of the first filamentport 216 and an orifice of the second filament port 218 connecting thefilament ports to the interior volume 204 are visible.

FIG. 10 shows the inlet die 402 having a shoulder 450, which may beretained between the proximal retaining plate 406 (FIG. 8) and thefastener 500 (FIG. 12A). FIG. 11 shows an alternative inlet die 452having a groove 454, which may be used to engage a clip, such as anE-clip or radial retaining ring.

FIGS. 12A-B show proximal and distal sides of various components of theheating cartridge 102 in an unassembled state. FIG. 12A shows theproximal sides, whereas FIG. 12B shows the distal sides.

As illustrated, the heating cartridge 102 includes the proximalretaining plate 406, the distal retaining plate 408, the heating block,and the fastener 500, which may be threaded into an aperture in theproximal side of the proximal retaining plate 406.

A side view of the heat break 238 is shown in FIG. 12A. As can be seen,the heat break 238 may include a necked portion and a couplingprotrusion (threaded).

In the illustrated embodiment, the heating block 202 includes twoexterior volumes 502, or notches or receptacles. The exterior volumes502 may be used to receive a heating element 104 (FIG. 1).

FIG. 13 shows one example of a catheter 600 that may be manufacturedusing the system 100 before the substrate 116 is removed. The substrate116 may include a lubricious coating on its exterior surface tofacilitate removal. The lubricious coating may extend around thecircumference of the substrate 116. One example of a lubricious coatingis a PTFE coating.

The substrate 116 may be covered with a liner 602, such as a PTFE layer.The liner 602 may be placed over the lubricious coating. The liner 602may extend around the circumference of the substrate 116.

The liner 602 may be covered with a braid 604, such as a stainless-steelbraid layer. The braid 604 may be placed over the liner 602. The braid604 may extend around the circumference of the liner 602. The braid 604may be porous.

The jacket 118 may be applied to the braid 604. When the jacket 118 isformed, the liner 602 may adhere to the jacket 118 through pores in thebraid 604.

In the illustrated embodiments, the catheter 600 includes a firstsegment 606, a second segment 608, and a third segment 610. Each segment606, 608, 610 may have different durometers. In some embodiments, thefirst segment 606 may have a high durometer, the third segment 610 mayhave a low durometer, and the second segment 608 may have a continuouslyvarying durometer in a longitudinal direction between the durometers ofthe first and third segments. For example, the first segment 606 mayhave a Shore durometer equal to 72 D, the third segment 610 may have aShore durometer equal to 35 D, and the second segment 608 may have aShore durometer that gradually changes from 72 D to 35 D over itslength.

FIG. 14 shows one example of a jacket 620 that may be formed using thesystem 100. The jacket 620 may include one or more protrusions 622forming at least part of the exterior surface of the jacket 620. Asillustrated, the protrusions 622 may be spiral or helical along thelength of the jacket 620. The spiral protrusions 622 may be used, forexample, as an auger to pull the catheter through tight, tortuousanatomy when rotating and pushing on the catheter no longer advance thecatheter to the target site.

The system 100 may, for example, rotate the substrate 116 (FIG. 1) orthe heating cartridge 102 (FIG. 1) relative to one another whiletranslating the substrate relative to the heating cartridge. The jacket620 may be formed using particular inlet or outlet dies (see FIGS.15-16).

FIG. 15 shows an end view of one example of an inlet or outlet die 700that may be used in the heating cartridge 102 (FIG. 1). The die 700 maydefine a substrate inlet or outlet port 702. The port 702 may define amain region 704 and one, two, three, four, or more cutouts 706, orcutout regions. In the illustrated embodiment, the port 702 defines fourcutouts 706.

When the interior cross-sectional shape die 700 is used in an outletdie, the jacket formed by the heating cartridge 102 may include a numberof protrusions corresponding to the number of cutouts 706 used in thedie 700. For example, the illustrated die 700 would produce fourprotrusions on the jacket.

In some embodiments, one or more of the cutouts 706 may be sized toreceive a wire 115 (FIG. 1), such as a pull wire, which may be providedby the wire handling system 107 (FIG. 1). In some embodiments, theinterior cross-sectional shape of die 700 may be used in both the inputdie and the outlet die to accommodate the wires 115 pulled through thecutouts 706. For example, FIG. 16 shows a perspective view of oneexample of an inlet die 710 having the interior cross-sectional shape ofthe die 700.

FIG. 17 shows an end view one example of an inlet or outlet die 720 thatmay be used in the heating cartridge 102 (FIG. 1). The die 720 maydefine a substrate inlet or outlet port 722. The port 722 may define amain region 724 and one, two, three, four, or more protrusions 726, orcutout regions. In the illustrated embodiment, the port 722 defines twoprotrusions 726, or teeth.

When the interior cross-sectional shape die 720 is used in an outletdie, the jacket formed by the heating cartridge 102 may include a numberof channels corresponding to the number of protrusions 726 used in thedie 720. For example, the illustrated die 720 would produce two channelson the jacket.

FIG. 18 shows a cross-sectional side view of one example of an outletdie 730 that may be used in the heating cartridge 102 (FIG. 1). The die730 may define a substrate outlet port 732. The port 732 may define aproximal portion 734 and a distal portion 736. The distal portion 736may have a width or diameter that is greater than the proximal portion734. The distal portion 736 may be described as a relieved portion. Thechange in diameter between the portions 734, 736 may define an interiorshoulder or a shoulder on the interior surface.

The outlet die 730 may be used to change a thickness of the jacket. Insome embodiments, the feeding force of the one or more filaments may beused to change the thickness of the jacket when used with the outlet die730. In one example, a catheter jacket may have an outer diameter of0.100 inches when running at a federate of F100 and an outer diameter of0.110 when running at a federate of F175.

FIG. 19 shows one example of a method 800 of using the system 100(FIG. 1) for additive manufacturing. The method 800 may be used tomanufacture an implantable medical catheter.

The method 800 may include feeding the substrate 802, for example,through a substrate channel in a heating cartridge. The substratechannel may be in fluid communication with an interior cavity of theheating cartridge.

The method 800 may include feeding one or more filaments 804. Forexample, at least a first filament may be fed through a filament port ofthe heating cartridge into the interior cavity. In some embodiments, asecond filament may be fed through another filament port into theinterior cavity.

The method 800 may include melting one or more of the filaments 806, forexample, in the interior cavity. Any portion of the filaments containedin the interior cavity may be melted. In some embodiments, a secondfilament is melted with the first filament.

The method 800 may include moving the heating cartridge relative to thesubstrate 808, for example, at least in a longitudinal direction to forma catheter jacket comprising material from at least the first filament.The heating cartridge or substrate may also be rotated relative to oneanother. The catheter jacket may be formed from material of at least thefirst filament. In some embodiments, the catheter jacket may be formedfrom material of at least the first filament and the second filament.

In some embodiments, the method 800 may also include adjusting a ratioof the first filament relative to the second filament over alongitudinal distance to change the Shore durometer of the catheterjacket over the longitudinal distance.

Illustrative Embodiments

While the present disclosure is not so limited, an appreciation ofvarious aspects of the disclosure will be gained through a discussion ofthe specific examples and illustrative embodiments provided below.Various modifications of the examples and illustrative embodiments, aswell as additional embodiments of the disclosure, will become apparentherein.

A1. An additive manufacturing apparatus comprising:

-   -   a heating block at least partially defining an interior volume        to allow an elongate substrate to pass through the interior        volume and through the heating block, wherein the heating block        at least partially defines a first filament port in fluid        communication with the interior volume; and    -   a first guide sheath coupled to the heating block and extending        into the first filament port from an exterior of the heating        block, the first guide sheath defining a lumen in fluid        communication with the interior volume.

A2. The apparatus according to embodiment A1, further comprising asupport element coupled to the first guide sheath proximate to theheating block

A3.The apparatus according to embodiment A2, wherein the support elementis a thermal insulator

A4. The apparatus according to embodiment A2 or A3, wherein the supportelement comprises a thermoplastic.

A5. The apparatus according to any one of embodiments A2 to A4, whereinthe support element comprises polyamide-imide.

A6. The apparatus according to any one of embodiments A2 to A5, whereinthe support element has a higher Shore durometer than the first guidesheath.

A7. The apparatus according to any one of embodiments A2 to A6, whereina distal end of the support element and a distal end of the first guidesheath engage a first shoulder defined by the first filament port.

A8. The apparatus according to any one of embodiments A2 to A6, whereina distal end of the support element engages a first shoulder defined bythe first filament port and the a distal end of the first guide sheathengages a second shoulder defined by the first filament port distal tothe first shoulder.

A9. The apparatus according to any preceding A embodiment, wherein adistal portion or distal end of the first guide sheath is proximate toor adjacent to the interior volume.

A10. The apparatus according to any preceding A embodiment, wherein thefirst guide sheath comprises a synthetic fluoropolymer.

A11. The apparatus according to any preceding A embodiment, wherein thefirst guide sheath comprises polytetrafluoroethylene.

A12. The apparatus according to any preceding A embodiment, furthercomprising an inlet die at least partially defining a substrate inletport and an outlet die at least partially defining a substrate outletport, wherein the interior volume is at least partially defined by theinlet die coupled to a proximal side of the heating block and at leastpartially defined by the outlet die coupled to the heating block at adistal side of the heating block.

A13. The apparatus according to embodiment A12, wherein one or both ofthe substrate inlet port and the substrate outlet port defines one, two,three, four, or more cutouts.

A14. The apparatus according to embodiment A13, wherein each cutout isconfigured to receive a pull wire.

A15. The apparatus according to any one of embodiments A12 to A14,wherein one or both of the substrate inlet port and the substrate outletport defines one, two, three, four, or more protrusions.

A16. The apparatus according to any one of embodiments A12 to A15,wherein one or both of the inlet die and the outlet die comprises aninterior shoulder.

A17. The apparatus according to any preceding A embodiment, wherein theheating block at least partially defines a second filament port in fluidcommunication with the interior volume.

A18. The apparatus according to embodiment A17, wherein a second guidesheath is coupled to a heat sink, the heat sink is coupled to a heatbreak, and the heat break at least partially extends into the secondfilament port and is coupled to the heating block.

A19. The apparatus according to any preceding A embodiment, furthercomprising one or more heating elements thermally coupled to the heatingblock to melt filament material in the interior volume.

B1. An additive manufacturing system comprising:

-   -   a heating cartridge extending from a proximal side to a distal        side and comprising a substrate inlet port at the proximal side        and a substrate outlet port at the distal side, the heating        cartridge defining an interior volume and a substrate channel        extending through the interior volume from the proximal side to        the distal side, wherein the heating cartridge defines a first        filament port in fluid communication with the interior volume to        receive the first filament and a second filament port in fluid        communication with the interior volume;    -   a heating element thermally coupled to the heating cartridge to        heat the interior volume;    -   a filament handling system comprising one or more motors to feed        at least a first filament through the first filament port and a        second filament through the second filament port into the        interior volume;    -   a substrate handling system comprising:        -   a head stock comprising a distal clamp to secure a distal            portion of an elongate substrate, wherein the substrate is            positioned to pass through the substrate channel when            secured by the head stock; and        -   one or more motors to translate or rotate one or both of the            substrate when secured by the headstock and the heating            cartridge relative to one another; and    -   a controller operably coupled to the heating element, one or        more motors of the filament handling system, and one or more        motors of the substrate handling system, the controller        configured to:        -   activate the heating element to melt any portion of the            first filament or the second filament in the interior            volume;        -   control the one or more motors of the filament handling            system to selectively control the feeding of the first            filament and the second filament into the interior volume;            and        -   control one or more motors of the substrate handling system            to move one or both of the substrate and the heating            cartridge relative to one another in at least a longitudinal            direction to form an elongate catheter jacket around the            substrate, wherein the catheter jacket comprises material            from at least one of the first filament and the second            filament.

B2. The system according to embodiment B1, wherein the heating cartridgecomprises a guide sheath extending into the first filament port, theguide sheath defining a lumen in fluid communication with the interiorvolume.

B3. The system according to embodiment B2, wherein the guide sheathextends between the filament handling system and the interior volume.

B4. The system according to embodiment B2 or B3, wherein a distalportion or distal end of the guide sheath is proximate to or adjacent tothe interior volume.

B5. The system according to any one of embodiments B2 to B4, wherein theheating cartridge comprises a support element coupled to the guidesheath.

B6. The system according to any preceding B embodiment, wherein thefirst filament has a Shore durometer less than or equal to 90 A, 80 A,70 A, 80 D, 72 D, 70 D, 60 D, 50 D, 40 D, or 35 D.

B7. The system according to any preceding B embodiment, wherein thefirst filament has a Shore durometer 10 D, 20 D, 30 D, 35 D, or 40 Dless than a Shore durometer of the second filament.

B8. The system according to any preceding B embodiment, wherein theheating cartridge comprises an inlet die, a heating block, and an outletdie, wherein heating block defines the first filament port and thesecond filament port.

B9. The system according to any preceding B embodiment, furthercomprising a concentricity guide defining a channel spacedlongitudinally from the heating cartridge positioned to engage thecatheter jacket.

B10. The system according to embodiment B9, wherein the concentricityguide comprises an adjustable member to laterally position the catheterjacket relative to the channel of the concentricity guide.

B11. The system according to any preceding B embodiment, wherein thefilament handling system comprises one, two, or more pinch rollersoperably coupled to the one or more motors of the filament handlingsystem to engage one or both of the first filament and the secondfilament.

B12. The system according to any preceding B embodiment, wherein one orboth of the substrate inlet port and the substrate outlet port definesone, two, three, four, or more cutouts, and the controller is configuredto rotate the substrate relative to the heating cartridge whiletranslating the substrate relative to the heating cartridge to form theelongate catheter jacket around the substrate.

B13. The system according to embodiment B12, further comprising a wirehandling system to provide a catheter pull wire to each of the cutouts.

B14. The system according to embodiment B12 or B13, wherein thesubstrate outlet port defines the one, two, three, four, or more cutoutsand the catheter jacket comprises a number of helical protrusionscorresponding to the number of cutouts.

B15. The system according to any preceding B embodiment, wherein one orboth of the substrate inlet port and the substrate outlet port definesone, two, three, four, or more protrusions.

B16. The system according to embodiment B15, wherein the substrateoutlet port includes the one, two, three, four, or more protrusions andthe catheter jacket comprises a corresponding number of channels.

B17. The system according to any preceding B embodiment, wherein thesubstrate outlet port of the heating cartridge defines an interiorshoulder, wherein the controller is configured to vary at least one of:a longitudinal speed of the substrate relative to the heating cartridge,a feeding force applied to at least one of the first filament and thesecond filament, and an amount of heat provided by the heating elementto change a thickness of the catheter jacket over a longitudinaldistance.

B18. The system according to any preceding B embodiment, wherein thecontroller is configured to change a feeding force applied to at leastone of the first filament and the second filament to change a ratio ofmaterial in the catheter jacket over a longitudinal distance.

B19. The system according to embodiment B18, wherein the change in ratioof material in the catheter jacket over the longitudinal distance iscontinuous.

B20. The system according to any preceding B embodiment, wherein thecontroller is configured to move the head stock in at least thelongitudinal direction away from the heating cartridge to form thecatheter jacket.

B21. The system according to any preceding B embodiment, wherein thesubstrate handling system comprises a tail stock comprising a proximalclamp to secure a proximal portion of the substrate.

B22. The system according to embodiment B21, wherein the controller isconfigured to move the heating cartridge in at least the longitudinaldirection away from the head stock to form the catheter jacket.

B23. The system according to any preceding B embodiment, furthercomprising the substrate, wherein the substrate comprises a lubriciouscoating, a liner, and a braid, and the catheter jacket is formed aroundthe braid.

C1. A method for additive manufacturing of an implantable medicalcatheter, the method comprising:

-   -   feeding a substrate through a substrate channel in a heating        cartridge, the substrate channel in fluid communication with an        interior cavity of the heating cartridge;    -   feeding at least a first filament through a filament port into        the interior cavity;    -   melting the first filament in the interior cavity; and    -   moving the heating cartridge relative to the substrate at least        in a longitudinal direction to form a catheter jacket comprising        material from at least the first filament.

C2. The method according to embodiment C1, further comprising:

-   -   feeding a second filament through another filament port into the        interior cavity; and    -   melting the second filament with the first filament to form the        catheter jacket comprising material from at least the first        filament and the second filament

C3. The method according to embodiment C2, further comprising adjustinga ratio of the first filament relative to the second filament over alongitudinal distance to change the Shore durometer of the catheterjacket over the longitudinal distance.

C4. The method according to any preceding C embodiment, wherein feedingthe first filament through the filament port comprises feeding the firstfilament through a guide sheath extending into the filament port.

C5. The method according to embodiment C4, wherein a distal portion ordistal end of the guide sheath is proximate to or adjacent to theinterior volume.

C6. The method according embodiment C4 or C5, wherein feeding the firstfilament through the filament port comprises feeding the first filamentthrough a support element coupled to the guide sheath.

C7. The method according to claim C6, wherein the support element has ahigher Shore durometer than the guide sheath.

Thus, various embodiments of ADDITIVE MANUFACTURING FOR MEDICAL DEVICESare disclosed. It should be understood that various aspects disclosedherein may be combined in different combinations than the combinationsspecifically presented in the description and accompanying drawings. Itshould also be understood that, depending on the example, certain actsor events of any of the processes or methods described herein may beperformed in a different sequence, may be added, merged, or left outaltogether (e.g., all described acts or events may not be necessary tocarry out the techniques). In addition, while certain aspects of thisdisclosure are described as being performed by a single module or unitfor purposes of clarity, it should be understood that the techniques ofthis disclosure may be performed by a combination of units or modulesassociated with, for example, a medical device.

In one or more examples, the described techniques may be implemented inhardware, software, firmware, or any combination thereof. If implementedin software, the functions may be stored as one or more instructions orcode on a computer-readable medium and executed by a hardware-basedprocessing unit. Computer-readable media may include non-transitorycomputer-readable media, which corresponds to a tangible medium such asdata storage media (e.g., RAM, ROM, EEPROM, flash memory, or any othermedium that can be used to store desired program code in the form ofinstructions or data structures and that can be accessed by a computer).

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor” as used herein may refer toany of the foregoing structure or any other physical structure suitablefor implementation of the described techniques. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

All references and publications cited herein are expressly incorporatedherein by reference in their entirety for all purposes, except to theextent any aspect directly contradicts this disclosure.

Unless otherwise indicated, all numbers expressing feature sizes,amounts, and physical properties used in the specification and claimsmay be understood as being modified either by the term “exactly” or“about.” Accordingly, unless indicated to the contrary, the numericalparameters set forth in the foregoing specification and attached claimsare approximations that can vary depending upon the desired propertiessought to be obtained by those skilled in the art utilizing theteachings disclosed herein or, for example, within typical ranges ofexperimental error.

As used herein, the term “configured to” may be used interchangeablywith the terms “adapted to” or “structured to” unless the content ofthis disclosure clearly dictates otherwise.

Th singular forms “a,” “an,” and “the” encompass embodiments havingplural referents unless its context clearly dictates otherwise.

As used herein, “have,” “having,” “include,” “including,” “comprise,”“comprising” or the like are used in their open-ended sense, andgenerally mean “including, but not limited to.” It will be understoodthat “consisting essentially of,” “consisting of,” and the like aresubsumed in “comprising,” and the like.

Reference to “one embodiment,” “an embodiment,” “certain embodiments,”or “some embodiments,” etc., means that a particular feature,configuration, composition, or characteristic described in connectionwith the embodiment is included in at least one embodiment of thedisclosure. Thus, the appearances of such phrases in various placesthroughout are not necessarily referring to the same embodiment of thedisclosure. Furthermore, the particular features, configurations,compositions, or characteristics may be combined in any suitable mannerin one or more embodiments.

The words “preferred” and “preferably” refer to embodiments of thedisclosure that may afford certain benefits, under certaincircumstances. However, other embodiments may also be preferred, underthe same or other circumstances. Furthermore, the recitation of one ormore preferred embodiments does not imply that other embodiments are notuseful and is not intended to exclude other embodiments from the scopeof the disclosure.

What is claimed:
 1. An additive manufacturing apparatus comprising: aheating block at least partially defining an interior volume to allow anelongate substrate to pass through the interior volume and through theheating block, wherein the heating block at least partially defines afirst filament port in fluid communication with the interior volume; anda first guide sheath coupled to the heating block and extending into thefirst filament port from an exterior of the heating block, the firstguide sheath defining a lumen in fluid communication with the interiorvolume.
 2. The apparatus of claim 1, further comprising a supportelement coupled to the first guide sheath proximate to the heatingblock.
 3. The apparatus of claim 2, wherein the support element is athermal insulator.
 4. The apparatus of claim 2, wherein the supportelement has a higher Shore durometer than the first guide sheath.
 5. Theapparatus of claim 2, wherein a distal end of the support element and adistal end of the first guide sheath engage a first shoulder defined bythe first filament port.
 6. The apparatus of claim 2, wherein a distalend of the support element engages a first shoulder defined by the firstfilament port and the a distal end of the first guide sheath engages asecond shoulder defined by the first filament port distal to the firstshoulder.
 7. The apparatus of claim 1, wherein a distal portion ordistal end of the first guide sheath is proximate to or adjacent to theinterior volume.
 8. The apparatus of claim 1, further comprising aninlet die at least partially defining a substrate inlet port and anoutlet die at least partially defining a substrate outlet port, whereinthe interior volume is at least partially defined by the inlet diecoupled to a proximal side of the heating block and at least partiallydefined by the outlet die coupled to the heating block at a distal sideof the heating block.
 9. The apparatus of claim 8, wherein one or bothof the inlet die and the outlet die comprises an interior shoulder. 10.The apparatus of claim 1, wherein the heating block at least partiallydefines a second filament port in fluid communication with the interiorvolume.
 11. The apparatus of claim 10, wherein a second guide sheath iscoupled to a heat sink, the heat sink is coupled to a heat break, andthe heat break at least partially extends into the second filament portand is coupled to the heating block.
 12. The apparatus of claim 1,further comprising one or more heating elements thermally coupled to theheating block to melt filament material in the interior volume.
 13. Anadditive manufacturing system comprising: a heating cartridge extendingfrom a proximal side to a distal side and comprising a substrate inletport at the proximal side and a substrate outlet port at the distalside, the heating cartridge defining an interior volume and a substratechannel extending through the interior volume from the proximal side tothe distal side, wherein the heating cartridge defines a first filamentport in fluid communication with the interior volume to receive thefirst filament and a second filament port in fluid communication withthe interior volume; a heating element thermally coupled to the heatingcartridge to heat the interior volume; a filament handling systemcomprising one or more motors to feed at least a first filament throughthe first filament port and a second filament through the secondfilament port into the interior volume; a substrate handling systemcomprising: a head stock comprising a distal clamp to secure a distalportion of an elongate substrate, wherein the substrate is positioned topass through the substrate channel when secured by the head stock; andone or more motors to translate or rotate one or both of the substratewhen secured by the headstock and the heating cartridge relative to oneanother; and a controller operably coupled to the heating element, oneor more motors of the filament handling system, and one or more motorsof the substrate handling system, the controller configured to: activatethe heating element to melt any portion of the first filament or thesecond filament in the interior volume; control the one or more motorsof the filament handling system to selectively control the feeding ofthe first filament and the second filament into the interior volume; andcontrol one or more motors of the substrate handling system to move oneor both of the substrate and the heating cartridge relative to oneanother in at least a longitudinal direction to form an elongatecatheter jacket around the substrate, wherein the catheter jacketcomprises material from at least one of the first filament and thesecond filament.
 14. The system of claim 13, wherein the heatingcartridge comprises a guide sheath extending into the first filamentport, the guide sheath defining a lumen in fluid communication with theinterior volume.
 15. The system of claim 14, wherein the guide sheathextends between the filament handling system and the interior volume.16. The system of claim 14, wherein a distal portion or distal end ofthe guide sheath is proximate to or adjacent to the interior volume. 17.The system of claim 14, wherein the heating cartridge comprises asupport element coupled to the guide sheath.
 18. The system of claim 13,wherein the first filament has a Shore durometer less than or equal to90 A, 80 A, 70 A, 80 D, 72 D, 70 D, 60 D, 50 D, 40 D, or 35 D.
 19. Thesystem of claim 13, wherein the first filament has a Shore durometer 10D, 20 D, 30 D, 35 D, or 40 D less than a Shore durometer of the secondfilament.
 20. The system of claim 13, wherein the heating cartridgecomprises an inlet die, a heating block, and an outlet die, whereinheating block defines the first filament port and the second filamentport.
 21. The system of claim 13, further comprising a concentricityguide defining a channel spaced longitudinally from the heatingcartridge positioned to engage the catheter jacket.
 22. The system ofclaim 21, wherein the concentricity guide comprises an adjustable memberto laterally position the catheter jacket relative to the channel of theconcentricity guide.
 23. The system of claim 13, wherein the substrateoutlet port of the heating cartridge defines an interior shoulder,wherein the controller is configured to vary at least one of: alongitudinal speed of the substrate relative to the heating cartridge, afeeding force applied to at least one of the first filament and thesecond filament, and an amount of heat provided by the heating elementto change a thickness of the catheter jacket over a longitudinaldistance.
 24. The system of claim 13, wherein the controller isconfigured to change a feeding force applied to at least one of thefirst filament and the second filament to change a ratio of material inthe catheter jacket over a longitudinal distance.
 25. The system ofclaim 24, wherein the change in ratio of material in the catheter jacketover the longitudinal distance is continuous.
 26. The system of claim13, wherein the controller is configured to move the head stock in atleast the longitudinal direction away from the heating cartridge to formthe catheter jacket.
 27. A method for additive manufacturing of animplantable medical catheter, the method comprising: feeding a substratethrough a substrate channel in a heating cartridge, the substratechannel in fluid communication with an interior cavity of the heatingcartridge; feeding at least a first filament through a filament portinto the interior cavity; melting the first filament in the interiorcavity; and moving the heating cartridge relative to the substrate atleast in a longitudinal direction to form a catheter jacket comprisingmaterial from at least the first filament.
 28. The method of claim 27,further comprising: feeding a second filament through another filamentport into the interior cavity; and melting the second filament with thefirst filament to form the catheter jacket comprising material from atleast the first filament and the second filament.
 29. The method ofclaim 28, further comprising adjusting a ratio of the first filamentrelative to the second filament over a longitudinal distance to changethe Shore durometer of the catheter jacket over the longitudinaldistance.
 30. The method of claim 27, wherein feeding the first filamentthrough the filament port comprises feeding the first filament through aguide sheath extending into the filament port.
 31. The method of claim30, wherein a distal portion or distal end of the guide sheath isproximate to or adjacent to the interior volume.
 32. The method of claim30, wherein feeding the first filament through the filament portcomprises feeding the first filament through a support element coupledto the guide sheath.
 33. The method of claim 32, wherein the supportelement has a higher Shore durometer than the guide sheath.